The Role of Plastic Deformation in Nanometer-Scale Wear

Abstract:

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Scratches on KBr(100) surfaces were produced and examined with an atomic force
microscope (AFM) operated in an ultra-high vacuum (UHV) environment. Scratches with lengths
on the order of 100s of nanometers and depths on the order of atomic layers were investigated.
Non-contact AFM topographic images of scratches revealed screw and edge dislocation activity
around the scratch sites, illuminating the role of plastic deformation in wear processes. Friction
coefficients of approximately 0.3 were measured during scratching, more comparable to
macroscopic friction experiments than those measured in low-load, single asperity experiments.

Abstract: Frequency modulation atomic force microscopy (FM-AFM) has been a powerful tool for imaging atomic-scale structures and properties of various materials including metals, semiconductors, metal oxides, alkali halides and organic systems. Whilst the method has been used mainly in ultrahigh vacuum environments, recent progress in FM-AFM instrumentation made it possible to apply this technique also to investigations in liquid. This technological innovation opened up a variety of applications of FM-AFM in biology and electrochemistry. To date, the improved FM-AFM instrument and technique have been applied to investigations of several biological materials, providing novel information that has not been accessible with other imaging techniques. In this review, I will summarize the recent progress in FM-AFM instrumentation and biological applications in liquid.

Abstract: The nano-thickness SiOx deposited on polyethylene terephthalate (PET) film and biaxially oriented polypropylene (BOPP) were fabricated by plasma enhanced chemical vapor deposition (PECVD) in a radio frequency (13.56 MHz) glow discharge. The nano-coatings were characterized by using Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and ultrasonic atomic force microscopy (UAFM). With AFM and UAFM, the topography and ultrasonic amplitude images were obtained. In particular, the UAFM images reveal the subsurface defects in the coating. The tensile property, contact angle and OTR of the PET present and absent of the SiOx coating were investigated experimentally respectively. The results can show that the SiOx coating can improved the barrier and the tensile strength.

Abstract: We have studied a step-in mode non-contact atomic force microscopy (NC-AFM) for precise measurement of fine and steep structure with nanometer resolution in air. When a high aspect structure is measured using step-in mode AFM with the sharpened and slim probe, it is required that AFM control has to be performed at a force of <1 nN in pico-Newton range to suppress the bending and slipping of the probe on slop. Using a home-made step-in mode NC-AFM using a quadrature frequency demodulator for resonant frequency shift of the cantilever, the NC-AFM demonstrated that Si steep structure was faithfully observed at about 2 pN in air.

Abstract: Micro interaction forces of lubricity surface of silicon and mica were studied using atomic force microscopy (AFM). From different scanning angle and bisection distance of the AFM, a new method of measuring micro static friction of lubricity surface materials was investigated. Results show that the micro coefficients of static and sliding friction of mica are less than the silicon, but the adhesive force is bigger. The mechanism of friction force of the two lubricity materials was discussed.

Abstract: Using the microwave atomic force microscope (M-AFM) measuring system, the sample of Au nanowires arranged on glass wafer was sensed with three kinds of scanning speed. As the results shown, the spatial resolution of topographies is increased with the decrease of scanning speed. However, the precision of microwave images is not changed much with decreasing the scanning speed. Since M-AFM with the compact microwave instrument can always implement the real time measurement, the variation of scanning speed will not affect the microwave measurement.